(223h) Mesoscale Simulations of Lipid Membranes Supported on Solid Surfaces

Using dissipative particle dynamics (DPD), we model lipid adsorption on solid supports. On metals and strongly hydrophobic substrates, lipids tend to adsorb in a lipid monolayer form. On hydrophilic and moderately hydrophobic surfaces, lipids adsorb in the bilayer form, with a water film of approximately 1-5 nm in width between the bilayer and the solid. Adhesion of silica to LB are to large extent determined by the free energy of the layer of water confined in the gap between the bilayer and the silica body. The very existence of the gap between silica and LB, as well as experimental measurements reported in the literature, testify that the disjoining pressure (a derivative of the characteristic thermodynamic potential by the distance between the bilayer and substrate) is non-monotonic and cannot be achieved with standard DPD potential. In order to enable non-monotonic disjoining pressure, we complement the DPD short-range repulsive potential with a long-range potential term between the support and the lipid tails. The parameters of the potential are fitted to the experimental and atomistic simulation results on disjoining pressure. With this model, we model lipid adhesion to hydrophobic and hydrophilic surfaces and consider the effect of surface curvature on lipid adhesion. This work was supported by NSF grant 1264702